Why your ability to repair a tractor could also be a matter of life and death | John Naughton

US farmers' struggles for the right to fix their own, now highly computer-controlled equipment, have implications for us all

It was one of the few pieces of cheery news to emerge from the war in Ukraine. Russian looters, no doubt with the assistance of Russian troops, stole 27 pieces of John Deere farm equipment, worth about $5m, from a dealership in Melitopol. The kit was shipped to Chechnya, where a nasty surprise awaited the crooks. Their shiny new vehicles had, overnight, become the world's heaviest paperweights: the dealership from which they had been stolen had bricked" them remotely, using an inbuilt kill-switch".

This news item no doubt warmed the cockles of many a western heart. But it would have raised only hollow laughs from farmers in US states who are customers of John Deere and are mightily pissed off, because although they have paid small fortunes (up to $800,000 apparently) for the firm's machinery, they are unable to service or repair them when they go wrong. These gigantic vehicles are no longer purely mechanical devices, but depend on lots of electronic control units (ECUs) to operate everything from the air conditioning to the driver's seat to the engine. The ICUs run software that is essential to the operation, maintenance and repair of the machine. But only John Deere has access to that computer code and without employing a company technician the tractor's software won't even recognise (let alone allow) replacement parts from another manufacturer.